[Endothelial-mesenchymal transition, ventricular remodeling after myocardial infarction, and research progress of Chinese medicine intervention].

Ventricular remodeling after myocardial infarction(VRAMI) is a pathological phenomenon triggered by the abrupt occlusion of coronary arteries, leading to myocardial ischemia and hypoxia. This intricate process encompasses alterations in the dimensions, composition, and elasticity of the ventricular tissue and reflects pathophysiological reactions and self-repair after cardiomyocytes are damaged. The characteristic pathological manifestation of VRAMI is the presence of myocardial fibrosis(MF), wherein fibrotic cardiac tissue undergoes a loss of contractile and relaxation capacity, ultimately culminating in heart failure(HF) and significantly impacting the patient's prognosis. Endothelial-mesenchymal transition(EndMT) is a biological process in which endothelial cells, in response to diverse pathological stimuli such as ischemia and hypoxia in the embryonic development period, undergo morphological alterations and functional impairment, progressively acquiring mesenchymal cell properties and ultimately differentiating into mesenchymal cells. The ongoing advancement of the EndMT process will result in an excessive buildup of collagen, thereby inducing structural harm to the myocardium and exacerbating the processes of VRAMI and MF. Recent investigations have demonstrated the pivotal involvement of EndMT in the pathological advancement of VRAMI. Consequently, a targeted intervention aimed at effectively impeding VRAMI, safeguarding cardiac function, and potentially serving as a novel therapeutic target for the prevention and treatment of VRAMI. This article provides a comprehensive review of recent Chinese and international literature, focusing on the role and pathophysiological mechanisms of EndMT in VRAMI. Additionally, it discusses the research progress of innovative targeted interventions using both traditional Chinese and Western medicine, so as to offer new insights and a theoretical foundation for the clinical treatment of the disease.

The antiangiogenic effect of total saponins of Panax japonicus C.A. Meyer in rheumatoid arthritis is mediated by targeting the HIF-1α/VEGF/ANG-1 axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese herbal medicine Panax japonicus C.A. Meyer has a long history in clinical treatment of rheumatoid arthritis (RA). Total saponins of Panax japonicus C.A. Meyer (TSPJs) were extracted from the root of Panax japonicus C.A. Meyer, and its anti-rheumatism mechanism is still unclear. AIM OF THE STUDY: To investigate whether TSPJs attenuated synovial angiogenesis in RA and explore the potential mechanisms. MATERIALS AND METHODS: Potential TSPJs targets involving gene function were predicted by network pharmacology related databases. Bioinformatics analysis and molecular docking technology were used to predict the mechanism of TSPJs in the treatment of RA. The predicted results were validated by cell experiments and a collagen-induced arthritis (CIA) mouse model. RESULTS: Bioinformatics analysis results showed that TSPJs may inhibit RA-related angiogenesis through the hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) pathways. In vitro, different doses of TSPJs showed a good inhibitory effect on the tube formation of EA.hy926 cells. The results of the cellular thermal shift assay indicated that TSPJs can bind to the HIF-1α, VEGFA, and angiopoietin-1 (ANG-1) proteins. In vivo, the administration of TSPJs alleviated the symptoms of CIA mice, including the arthritis index, hind paw thickness, and swollen joint count. The histological results demonstrated that TSPJs inhibited inflammation, angiogenesis, bone damage, and cartilage destruction. Furthermore, TSPJs decreased the number of vessels and the expression level of CD31. The mechanistic results revealed that TSPJs decreased the expression of HIF-1α, VEGFA, and ANG-1 in the serum or synovial tissues of CIA mice. CONCLUSION: These results suggest that TSPJs effectively inhibit angiogenesis in RA, and the mechanism may be related to inhibiting the HIF-1α/VEGF/ANG-1 axis.

Crosstalk between ferroptosis and necroptosis in cerebral ischemia/reperfusion injury and Naotaifang formula exerts neuroprotective effect via HSP90-GCN2-ATF4 pathway.

BACKGROUND: Cerebral ischemia/reperfusion injury (CIRI) is a sequence of pathophysiological processes after blood recanalization in the patients with ischemic stroke, and has become the hinder for the rehabilitation. Naotaifang formula (NTF) has exhibited the clinical effectiveness for this disease. However, its action effects and molecular mechanisms against CIRI are not fully elucidated. PURPOSE: The research was to clarify the crosstalk between ferroptosis and necroptosis in CIRI, and uncover the mechanism underlying the neuroprotection of NTF. METHODS: This study established MCAO/R rat models with various reperfusion times. Western blot, transmission electron microscope, laser speckle imaging, immunofluorescence, immunohistochemistry and pathological staining were conducted to detect and analyze the obtained results. Subsequently, various NTF doses were used to intervene in MCAO/R rats, and biology experiments, such as western blot, Evans blue, immunofluorescence and immunohistochemistry, were used to analyze the efficacy of NTF doses. The effect of NTF was further clarified through in vitro experiments. Eventually, HT22 cells that suffered OGD/R were subjected to pre-treatment with plasmids overexpressing HSP90, MLKL, and GPX4 to indicate the interaction among ferroptosis and necroptosis. RESULTS: There was a gradual increase in the Zea Longa score and cerebral infarction volume following CIRI with prolonged reperfusion. Furthermore, the expression of factors associated with pro-ferroptosis and pro-necroptosis was upregulated in the cortex and hippocampus. NTF alleviated ferroptosis and necroptosis in a dose-dependent manner, downregulated HSP90 levels, reduced blood-brain barrier permeability, and thus protected nerve cells from CIRI. The results in vitro research aligned with those of the in vivo research. HSP90 and MLKL overexpression promoted necroptosis and ferroptosis while activating the GCN2-ATF4 pathway. GPX4 overexpression had no effect on necroptosis or the associated signaling pathway. The administration of NTF alone, as well as its combination with the overexpression of HSP90, MLKL, or GPX4 plasmids, decreased the expression levels of factors associated with pro-ferroptosis and pro-necroptosis and reduced the protein levels of the HSP90-GCN2-ATF4 pathway. Moreover, the regulatory effects of the NTF alone group on GSH, ferrous iron, and GCN2 were more significant compared with those of the HSP90 overexpression combination group. CONCLUSION: Ferroptosis and necroptosis were gradually aggravated following CIRI with prolonged reperfusion. MLKL overexpression may promote ferroptosis and necroptosis, while GPX4 overexpression may have little effect on necroptosis. HSP90 overexpression accelerated both forms of cell death via the HSP90-GCN2-ATF4 pathway. NTF alleviated ferroptosis and necroptosis to attenuate CIRI by regulating the HSP90-GCN2-ATF4 pathway. Our research provided evidence for the potential of drug development by targeting HSP90, MLKL, and GPX4 to protect against ischemic stroke.

A novel rat model of cerebral small vessel disease based on vascular risk factors of hypertension, aging, and cerebral hypoperfusion.

Cerebral small vessel disease (CSVD) is a major cause of vascular cognitive impairment and functional loss in elderly patients. Progressive remodeling of cerebral microvessels due to arterial hypertension or other vascular risk factors, such as aging, can cause dementia or stroke. Typical imaging characteristics of CSVD include cerebral microbleeds (CMB), brain atrophy, small subcortical infarctions, white matter hyperintensities (WMH), and enlarged perivascular spaces (EPVS). Nevertheless, no animal models that reflect all the different aspects of CSVD have been identified. Here, we generated a new CSVD animal model using D-galactose (D-gal) combined with cerebral hypoperfusion in spontaneously hypertensive rats (SHR), which showed all the hallmark pathological features of CSVD and was based on vascular risk factors. SHR were hypodermically injected with D-gal (400 mg/kg/d) and underwent modified microcoil bilateral common carotid artery stenosis surgery. Subsequently, neurological assessments and behavioral tests were performed, followed by vascular ultrasonography, electron microscopy, flow cytometry, and histological analyses. Our rat model showed multiple cerebrovascular pathologies, such as CMB, brain atrophy, subcortical small infarction, WMH, and EPVS, as well as the underlying causes of CSVD pathology, including oxidative stress injury, decreased cerebral blood flow, structural and functional damage to endothelial cells, increased blood-brain barrier permeability, and inflammation. The use of this animal model will help identify new therapeutic targets and subsequently aid the development and testing of novel therapeutic interventions. Main process of the study: Firstly, we screened for optimal conditions for mimicking aging by injecting D-gal into rats for 4 and 8 weeks. Subsequently, we performed modified microcoil BCAS intervention for 4 and 8 weeks in rats to screen for optimal hypoperfusion conditions. Finally, based on these results, we combined D-gal for 8 weeks and modified microcoil BCAS for 4 weeks to explore the changes in SHR.

Novel insight into the role of A-kinase anchoring proteins (AKAPs) in ischemic stroke and therapeutic potentials.

Ischemic stroke, a devastating disease associated with high mortality and disability worldwide, has emerged as an urgent public health issue. A-kinase anchoring proteins (AKAPs) are a group of signal-organizing molecules that compartmentalize and anchor a wide range of receptors and effector proteins and have a major role in stabilizing mitochondrial function and promoting neurodevelopmental development in the central nervous system (CNS). Growing evidence suggests that dysregulation of AKAPs expression and activity is closely associated with oxidative stress, ion disorder, mitochondrial dysfunction, and blood-brain barrier (BBB) impairment in ischemic stroke. However, the underlying mechanisms remain inadequately understood. This review provides a comprehensive overview of the composition and structure of A-kinase anchoring protein (AKAP) family members, emphasizing their physiological functions in the CNS. We explored in depth the molecular and cellular mechanisms of AKAP complexes in the pathological progression and risk factors of ischemic stroke, including hypertension, hyperglycemia, lipid metabolism disorders, and atrial fibrillation. Herein, we highlight the potential of AKAP complexes as a pharmacological target against ischemic stroke in the hope of inspiring translational research and innovative clinical approaches.

THSG alleviates cerebral ischemia/reperfusion injury via the GluN2B-CaMKII-ERK1/2 pathway.

BACKGROUND: The potential therapeutic targeting of PINK1-PARK2-mediated mitophagy against cerebral ischemia/reperfusion (CI/R) injury involves the pathophysiological processes of neurovascular unit (NVU) and is closely associated with N-methyl-D-aspartate receptors (NMDARs) commonly expressed in NVU. 2,3,5,4'-Tetrahydroxy-stilbene-2-O-ß-D-glucoside (THSG), a compound derived from the traditional Chinese medicine Polygonum multiflorum Thunb., has demonstrated notable neuroprotective properties against CI/R injury. However, it remains unclear whether THSG exerts its protective effects through GluN2B related PINK1/ PARK2 pathway. PURPOSE: This study aims to explore the pharmacological effects of THSG on alleviating CI/R injury via the GluN2B-CaMKII-ERK1/2 pathway. METHODS: THSG neuroprotection against CI/R injury was studied in transient middle cerebral artery occlusion/reversion (tMCAO/R) model rats and in oxygen and glucose deprivation/ reoxygenation (OGD/R) induced neurons. PINK1-PARK2-mediated mitophagy involvement in the protective effect of THSG was investigated in tMCAO/R rats and OGD/R-induced neurons via THSG and 3-methyladenine (3-MA) treatment. Furthermore, the beneficial role of GluN2B in reperfusion and its contribution to the THSG effect via CaMKII-ERK1/2 and PINK1-PARK2-mediated mitophagy was explored using the GluN2B-selective antagonist Ro 25-6981 both in vivo and in vitro. Finally, the interaction between THSG and GluN2B was evaluated using molecular docking. RESULTS: THSG significantly reduced infarct volume, neurological deficits, penumbral neuron structure, and functional damage, upregulated the inhibitory apoptotic marker Bcl-2, and suppressed the increase of pro-apoptotic proteins including cleaved caspase-3 and Bax in tMCAO/R rats. THSG (1 µM) markedly improved the neuronal survival under OGD/R conditions. Furthermore, THSG promoted PINK1 and PARK2 expression and increased mitophagosome numbers and LC3-II-LC3-I ratio both in vivo and in vitro. The effects of THSG were considerably abrogated by the mitophagy inhibitor 3-MA in OGD/R-induced neurons. Inhibiting GluN2B profoundly decreased mitophagosome numbers and OGD/R-induced neuronal viability. Specifically, inhibiting GluN2B abolished the protection of THSG against CI/R injury and reversed the upregulation of PINK1-PARK2-mediated mitophagy by THSG. Inhibiting GluN2B eliminated THSG upregulation of ERK1/2 and CaMKII phosphorylation. The molecular docking analysis results demonstrated that THSG bound to GluN2B (binding energy: -5.2 ± 0.11 kcal/mol). CONCLUSIONS: This study validates the premise that THSG alleviates CI/R injury by promoting GluN2B expression, activating CaMKII and ERK1/2, and subsequently enhancing PINK1-PARK2-mediated mitophagy. This work enlightens the potential of THSG as a promising candidate for novel therapeutic strategies for treating ischemic stroke.

Astragaloside IV combined with ligustrazine ameliorates abnormal mitochondrial dynamics via Drp1 SUMO/deSUMOylation in cerebral ischemia-reperfusion injury.

OBJECTIVES: Astragaloside IV (AST IV) and ligustrazine (Lig), the main ingredients of Astragali Radix and Chuanxiong Rhizoma respectively, have demonstrated significant benefits in treatment of cerebral ischemia -reperfusion injury (CIRI); however, the mechanisms underlying its benificial effects remain unclear. SUMO-1ylation and deSUMO-2/3ylation of dynamin-related protein 1 (Drp1) results in mitochondrial homeostasis imbalance following CIRI, which subsequently aggravates cell damage. This study investigates the mechanisms by which AST IV combined with Lig protects against CIRI, focusing on the involvement of SUMOylation in mitochondrial dynamics. METHODS: Rats were administrated AST IV and Lig for 7 days, and middle cerebral artery occlusion was established to mimic CIRI. Neural function, cerebral infarction volume, cerebral blood flow, cognitive function, cortical pathological lesions, and mitochondrial morphology were measured. SH-SY5Y cells were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) injury. Mitochondrial membrane potential and lactic dehydrogenase (LDH), reactive oxygen species (ROS), and adenosine triphosphate (ATP) levels were assessed with commercial kits. Moreover, co-immunoprecipitation (Co-IP) was used to detect the binding of SUMO1 and SUMO2/3 to Drp1. The protein expressions of Drp1, Fis1, MFF, OPA1, Mfn1, Mfn2, SUMO1, SUMO2/3, SENP1, SENP2, SENP3, SENP5, and SENP6 were measured using western blot. RESULTS: In rats with CIRI, AST IV and Lig improved neurological and cognitive functions, restored CBF, reduced brain infarct volume, and alleviated cortical neuron and mitochondrial damage. Moreover, in SH-SY5Y cells, the combination of AST IV and Lig enhanced cellular viability, decreased release of LDH and ROS, increased ATP content, and improved mitochondrial membrane potential. Furthermore, AST IV combined with Lig reduced the binding of Drp1 with SUMO1, increased the binding of Drp1 with SUMO2/3, suppressed the expressions of Drp1, Fis1, MFF, and SENP3, and increased the expressions of OPA1, Mfn1, Mfn2, SENP1, SENP2, and SENP5. SUMO1 overexpression promoted mitochondrial fission and inhibited mitochondrial fusion, whereas SUMO2/3 overexpression suppressed mitochondrial fission. AST IV combined with Lig could reverse the effects of SUMO1 overexpression while enhancing those of SUMO2/3 overexpression. CONCLUSIONS: This study posits that the combination of AST IV and Lig has the potential to reduce the SUMO-1ylation of Drp1, augment the SUMO-2/3ylation of Drp1, and thereby exert a protective effect against CIRI.

[Effect of Naotaifang on microglial polarization and glial scar following cerebral ischemia reperfusion injury].

This study aims to investigate the effect of Naotaifang(NTF) on the proteins associated with microglial polarization and glial scar in the rat model of cerebral ischemia reperfusion injury(CIRI). The CIRI model was established by middle cerebral artery occlusion/reperfusion. The 48 successfully modeled rats were randomized into model 7 d, model 14 d, NTF 7 d, and NTF 14 d groups(n=12). In addition, 12 SD rats were selected as the sham group. The NTF group was administrated with NTF suspension at 27 g·kg~(-1)·d~(-1) by gavage, and the sham, model 7 d, and model 14 d groups were administrated with the same volume of normal saline every day by gavage for 7 and 14 days, respectively. After the intervention, Longa score was evaluated. The infarct volume was measured by 2,3,5-triphenyl-2H-tetrazolium chloride(TTC) staining. Morris water maze and open field tests were carried out to evaluate the spatial learning, memory, cognitive function, and anxiety degree of rats. Hematoxylin-eosin(HE) staining was employed to observe the morphological structure and damage of the brain tissue. The immunofluorescence assay was employed to measure the expression of glial fibrillary acidic protein(GFAP) and glial scar. Western blot was employed to determine the protein levels of GFAP, neurocan, phosphacan, CD206, arginase-1(Arg-1), interleukin(IL)-1ß, IL-6, and IL-4. Compared with the sham, model 7 d and model 14 d groups showed cerebral infarction of different degrees, severe pathological injury of cerebral cortex and hippocampus, neurological impairment, reduced spatial learning and memory, cognitive dysfunction, severe anxiety, astrocyte hyperplasia, thickening penumbra glial scar, and up-regulated protein levels of IL-1ß, IL-6, GFAP, neurocan, phosphacan, CD206, and Arg-1(P<0.01). Compared with the model group, NTF 7 d and NTF 14 d groups improved spatial learning, memory, and cognitive function, reduced anxiety, improved nerve function, reduced cerebral infarction volume, reduced astrocyte hyperplasia, thinned penumbra glial scar, down-regulated the protein levels of GFAP, neurocan, phosphacan, IL-6, and IL-1ß, and up-regulated the protein levels of IL-4, CD206, and Arg-1(P<0.05 or P<0.01). NTF exerts a neuroprotective effect on CIRI by inducing the M2 polarization of microglia, inhibiting inflammatory response, and reducing the formation of glial scar.

Novel insight into the therapeutical potential of flavonoids from traditional Chinese medicine against cerebral ischemia/reperfusion injury.

Cerebral ischemia/reperfusion injury (CIRI) is a major contributor to poor prognosis of ischemic stroke. Flavonoids are a broad family of plant polyphenols which are abundant in traditional Chinese medicine (TCM) and have beneficial effects on several diseases including ischemic stroke. Accumulating studies have indicated that flavonoids derived from herbal TCM are effective in alleviating CIRI after ischemic stroke in vitro or in vivo, and exhibit favourable therapeutical potential. Herein, we systematically review the classification, metabolic absorption, neuroprotective efficacy, and mechanisms of TCM flavonoids against CIRI. The literature suggest that flavonoids exert potential medicinal functions including suppressing excitotoxicity, Ca2+ overloading, oxidative stress, inflammation, thrombin's cellular toxicity, different types of programmed cell deaths, and protecting the blood-brain barrier, as well as promoting neurogenesis in the recovery stage following ischemic stroke. Furthermore, we identified certain matters that should be taken into account in future research, as well as proposed difficulties and opportunities in transforming TCM-derived flavonoids into medications or functional foods for the treatment or prevention of CIRI. Overall, in this review we aim to provide novel ideas for the identification of new prospective medication candidates for the therapeutic strategy against ischemic stroke.

No-reflow after recanalization in ischemic stroke: From pathomechanisms to therapeutic strategies.

Endovascular reperfusion therapy is the primary strategy for acute ischemic stroke. No-reflow is a common phenomenon, which is defined as the failure of microcirculatory reperfusion despite clot removal by thrombolysis or mechanical embolization. It has been reported that up to 25% of ischemic strokes suffer from no-reflow, which strongly contributes to an increased risk of poor clinical outcomes. No-reflow is associated with functional and structural alterations of cerebrovascular microcirculation, and the injury to the microcirculation seriously hinders the neural functional recovery following macrovascular reperfusion. Accumulated evidence indicates that pathology of no-reflow is linked to adhesion, aggregation, and rolling of blood components along the endothelium, capillary stagnation with neutrophils, astrocytes end-feet, and endothelial cell edema, pericyte contraction, and vasoconstriction. Prevention or treatment strategies aim to alleviate or reverse these pathological changes, including targeted therapies such as cilostazol, adhesion molecule blocking antibodies, peroxisome proliferator-activated receptors (PPARs) activator, adenosine, pericyte regulators, as well as adjunctive therapies, such as extracorporeal counterpulsation, ischemic preconditioning, and alternative or complementary therapies. Herein, we provide an overview of pathomechanisms, predictive factors, diagnosis, and intervention strategies for no-reflow, and attempt to convey a new perspective on the clinical management of no-reflow post-ischemic stroke.

Metabolic Reprogramming in Gliocyte Post-cerebral Ischemia/ Reperfusion: From Pathophysiology to Therapeutic Potential.

Ischemic stroke is a leading cause of disability and death worldwide. However, the clinical efficacy of recanalization therapy as a preferred option is significantly hindered by reperfusion injury. The transformation between different phenotypes of gliocytes is closely associated with cerebral ischemia/ reperfusion injury (CI/RI). Moreover, gliocyte polarization induces metabolic reprogramming, which refers to the shift in gliocyte phenotype and the overall transformation of the metabolic network to compensate for energy demand and building block requirements during CI/RI caused by hypoxia, energy deficiency, and oxidative stress. Within microglia, the pro-inflammatory phenotype exhibits upregulated glycolysis, pentose phosphate pathway, fatty acid synthesis, and glutamine synthesis, whereas the anti-inflammatory phenotype demonstrates enhanced mitochondrial oxidative phosphorylation and fatty acid oxidation. Reactive astrocytes display increased glycolysis but impaired glycogenolysis and reduced glutamate uptake after CI/RI. There is mounting evidence suggesting that manipulation of energy metabolism homeostasis can induce microglial cells and astrocytes to switch from neurotoxic to neuroprotective phenotypes. A comprehensive understanding of underlying mechanisms and manipulation strategies targeting metabolic pathways could potentially enable gliocytes to be reprogrammed toward beneficial functions while opening new therapeutic avenues for CI/RI treatment. This review provides an overview of current insights into metabolic reprogramming mechanisms in microglia and astrocytes within the pathophysiological context of CI/RI, along with potential pharmacological targets. Herein, we emphasize the potential of metabolic reprogramming of gliocytes as a therapeutic target for CI/RI and aim to offer a novel perspective in the treatment of CI/RI.

Naotaifang III Protects Against Cerebral Ischemia Injury Through LPS/TLR4 Signaling Pathway in the Microbiota-Gut-Brain Axis.

Background: Ischemic stroke (IS) is a leading cause of mortality worldwide. Naotaifang III is a new Chinese herbal formula to treat IS. Previous studies have shown that Astragali Radix, Puerariae Lobatae Radix, Chuanxiong Rhizoma, and Rhei Radix Et Rhizoma in Naotaifang III were able to regulate the imbalance of intestinal microbiota during cerebral ischemia injury. Methods: Rats were randomly divided into sham operation group, normal control group, middle cerebral artery occlusion (MCAO) group, intestinal microbiota imbalance MCAO group, Naotaifang III group, and normal bacteria transplantation group, with 15 rats in each group. Then, neurological function scores and cerebral infarction volume were detected; haematoxylin and eosin staining and Golgi silver staining were used to observe morphological changes in brain tissue. Meanwhile, the lipopolysaccharide (LPS) and cerebral cortex interleukin (IL)-1ß were detected by enzyme-linked immunosorbent assay (ELISA); the expressions of Toll-like receptor (TLR)-4 and nuclear factor kappa-B (NF-κB) proteins were detected by immunofluorescence and Western blot. The cecal flora was detected by 16S rDNA. The results showed that gut dysbiosis aggravated cerebral ischemic injury and significantly increased the expression of LPS, TLR4, NF-κB, and IL-1ß, which could be significantly reversed by Naotaifang III or normal bacterial transplantation. Naotaifang III may exert a protective effect on neuroinflammatory injury after MCAO through the LPS/TLR4 signaling pathway in the microbe-gut-brain axis. In summary, Naotaifang III may induce anti-neuroinflammatory molecular mechanisms and signaling pathways through the microbe-gut-brain axis. Results: The results showed that gut dysbiosis aggravated cerebral ischemic injury and significantly increased the expression of LPS, TLR4, NF-κB, and IL-1ß, which could be significantly reversed by Naotaifang III or normal bacterial transplantation. Naotaifang III may exert a protective effect on neuroinflammatory injury after MCAO through the LPS/TLR4 signaling pathway in the microbe-gut-brain axis. Conclusion: Naotaifang III may induce anti-neuroinflammatory molecular mechanisms and signaling pathways through the microbe-gut-brain axis.

Novel insight into cGAS-STING pathway in ischemic stroke: from pre- to post-disease.

Ischemic stroke, a primary cause of disability and the second leading cause of mortality, has emerged as an urgent public health issue. Growing evidence suggests that the Cyclic GMP-AMP synthase (cGAS)- Stimulator of interferon genes (STING) pathway, a component of innate immunity, is closely associated with microglia activation, neuroinflammation, and regulated cell death in ischemic stroke. However, the mechanisms underlying this pathway remain inadequately understood. This article comprehensively reviews the existing literature on the cGAS-STING pathway and its multifaceted relationship with ischemic stroke. Initially, it examines how various risk factors and pre-disease mechanisms such as metabolic dysfunction and senescence (e.g., hypertension, hyperglycemia, hyperlipidemia) affect the cGAS-STING pathway in relation to ischemic stroke. Subsequently, we explore in depth the potential pathophysiological relationship between this pathway and oxidative stress, endoplasmic reticulum stress, neuroinflammation as well as regulated cell death including ferroptosis and PANoptosis following cerebral ischemia injury. Finally, it suggests that intervention targeting the cGAS-STING pathway may serve as promising therapeutic strategies for addressing neuroinflammation associated with ischemic stroke. Taken together, this review concludes that targeting the microglia cGAS-STING pathway may shed light on the exploration of new therapeutic strategies against ischemic stroke.

New Wine in an Old Bottle: tPA for Ischemic Stroke Management.

As the only clinical thrombolytic drug approved by the FDA, tissue-type plasminogen activator (tPA) is the good standard acute treatment against ischemic stroke (IS) during the super-early stage. tPA forms the active principle of alteplase, a recombinant tissue-type plasminogen activator (rtPA), which is well known for its intravascular thrombolytic activity. However, the multifaceted functions of tPA in the central nervous system (CNS) hold untapped potential. Currently, increasing studies have explored the neuroprotective function of tPA in neurological diseases, particularly in acute ischemic stroke (AIS). A series of studies have indicated that tPA has anti-excitotoxic, neurotrophic, and anti-apoptotic effects on neurons; it is also involved in neuronal plasticity, axonal regeneration, and cerebral inflammatory processes, but how to deeply understand the underlying mechanism and take maximum advantage of tPA seems to be urgent. Therefore, more work is needed to illuminate how tPA performs with more diverse functions after stroke onset. In this comment, we focus on possible hypotheses about why and how tPA promotes ischemic neuronal survival in a comprehensive view. The text provides a holistic picture of the functions of tPA and enlists the considerations for the future, which might attract more attention toward the therapeutic potential of tPA in AIS.

The Interplay between Mitochondrial Dysfunction and Ferroptosis during Ischemia-Associated Central Nervous System Diseases.

Cerebral ischemia, a leading cause of disability and mortality worldwide, triggers a cascade of molecular and cellular pathologies linked to several central nervous system (CNS) disorders. These disorders primarily encompass ischemic stroke, Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy, and other CNS conditions. Despite substantial progress in understanding and treating the underlying pathological processes in various neurological diseases, there is still a notable absence of effective therapeutic approaches aimed specifically at mitigating the damage caused by these illnesses. Remarkably, ischemia causes severe damage to cells in ischemia-associated CNS diseases. Cerebral ischemia initiates oxygen and glucose deprivation, which subsequently promotes mitochondrial dysfunction, including mitochondrial permeability transition pore (MPTP) opening, mitophagy dysfunction, and excessive mitochondrial fission, triggering various forms of cell death such as autophagy, apoptosis, as well as ferroptosis. Ferroptosis, a novel type of regulated cell death (RCD), is characterized by iron-dependent accumulation of lethal reactive oxygen species (ROS) and lipid peroxidation. Mitochondrial dysfunction and ferroptosis both play critical roles in the pathogenic progression of ischemia-associated CNS diseases. In recent years, growing evidence has indicated that mitochondrial dysfunction interplays with ferroptosis to aggravate cerebral ischemia injury. However, the potential connections between mitochondrial dysfunction and ferroptosis in cerebral ischemia have not yet been clarified. Thus, we analyzed the underlying mechanism between mitochondrial dysfunction and ferroptosis in ischemia-associated CNS diseases. We also discovered that GSH depletion and GPX4 inactivation cause lipoxygenase activation and calcium influx following cerebral ischemia injury, resulting in MPTP opening and mitochondrial dysfunction. Additionally, dysfunction in mitochondrial electron transport and an imbalanced fusion-to-fission ratio can lead to the accumulation of ROS and iron overload, which further contribute to the occurrence of ferroptosis. This creates a vicious cycle that continuously worsens cerebral ischemia injury. In this study, our focus is on exploring the interplay between mitochondrial dysfunction and ferroptosis, which may offer new insights into potential therapeutic approaches for the treatment of ischemia-associated CNS diseases.

Naotaifang formula attenuates OGD/R-induced inflammation and ferroptosis by regulating microglial M1/M2 polarization through BMP6/SMADs signaling pathway.

BACKGROUND: Cerebral ischemia-reperfusion injury (CIRI), a subsequent injury caused by thrombolytic reperfusion post ischemic stroke (IS). Naotaifang (NTF) formula, a novel traditional Chinese medicine (TCM) remedy against IS, was shown to exert beneficial effects in inhibiting inflammation and inhibiting lipid peroxide synthesis in our previous research. PURPOSE: This study aimed to further explore the role of NTF in attenuating oxygen-glucose deprivation//reoxygenation (OGD/R)-induced inflammation and ferroptosis by regulating microglial M1/M2 polarization through the bone morphogenetic protein 6（BMP6）/SMADs signaling pathway. METHODS: BV2 microglia were used to establish an OGD/R model. The effects of NTF on inflammation and ferroptosis in OGD/R-injured BV2 cells were separately detected by immunofluorescence assay, fluorescent probe, DCFH-DA flow cytometry, enzyme-linked immunosorbent assay, and western-blot. RESULTS: The present results revealed that the M1 phenotype of microglia promoted the secretion of pro-inflammatory cytokines and aggravated ferroptosis and brain damage following OGD/R. However, an inhibitor of BMP6, LND-193189, reversed the aforementioned effects. Similarly, NTF promoted the shift of microglia from M1 to M2. Besides, NTF treatment effectively inhibited the expression of hepcidin, BMP6, SMADs and promoted the expression of ferroportin (FPN, SLC40A1) and γ-L-glutamyl-L-cysteinylglycine (glutathione or GSH) peroxidase 4 (GPX4). CONCLUSION: Microglial M1/M2 polarization plays a pivotal role in inflammation and ferroptosis during OGD/R. The BMP6/SMADs signaling pathway is a potential therapeutical target of inflammation and ferroptosis induced by the transformation of microglia. Moreover, NTF could alleviate inflammation and ferroptosis through the BMP6/SMADs signaling pathway in OGD/R-injured microglia.

Mitochondrial dysfunctions induce PANoptosis and ferroptosis in cerebral ischemia/reperfusion injury: from pathology to therapeutic potential.

Ischemic stroke (IS) accounts for more than 80% of the total stroke, which represents the leading cause of mortality and disability worldwide. Cerebral ischemia/reperfusion injury (CI/RI) is a cascade of pathophysiological events following the restoration of blood flow and reoxygenation, which not only directly damages brain tissue, but also enhances a series of pathological signaling cascades, contributing to inflammation, further aggravate the damage of brain tissue. Paradoxically, there are still no effective methods to prevent CI/RI, since the detailed underlying mechanisms remain vague. Mitochondrial dysfunctions, which are characterized by mitochondrial oxidative stress, Ca2+ overload, iron dyshomeostasis, mitochondrial DNA (mtDNA) defects and mitochondrial quality control (MQC) disruption, are closely relevant to the pathological process of CI/RI. There is increasing evidence that mitochondrial dysfunctions play vital roles in the regulation of programmed cell deaths (PCDs) such as ferroptosis and PANoptosis, a newly proposed conception of cell deaths characterized by a unique form of innate immune inflammatory cell death that regulated by multifaceted PANoptosome complexes. In the present review, we highlight the mechanisms underlying mitochondrial dysfunctions and how this key event contributes to inflammatory response as well as cell death modes during CI/RI. Neuroprotective agents targeting mitochondrial dysfunctions may serve as a promising treatment strategy to alleviate serious secondary brain injuries. A comprehensive insight into mitochondrial dysfunctions-mediated PCDs can help provide more effective strategies to guide therapies of CI/RI in IS.

An update on the role of Hippo signaling pathway in ischemia-associated central nervous system diseases.

The most frequent reason of morbidity and mortality in the world, cerebral ischemia sets off a chain of molecular and cellular pathologies that associated with some central nervous system (CNS) disorders mainly including ischemic stroke, Alzheimer's disease (AD), Parkinson's disease (PD), epilepsy and other CNS diseases. In recent times, despite significant advancements in the treatment of the pathological processes underlying various neurological illnesses, effective therapeutic approaches that are specifically targeted to minimizing the damage of such diseases remain absent. Hippo signaling pathway, characterized by enzyme linked reactions between MSTI/2, LAST1/2, and YAP or TAZ proteins, controls cell division, survival, and differentiation, as well as being engaged in a variety of biological activities, such as the development and transformation of the nervous system. Recently, accumulating studies demonstrated that Hippo pathway takes part in the processes of ischemic stroke, AD, PD, etc., including but not limited to oxidative stress, inflammatory response, blood-brain barrier damage, mitochondrial disorders, and neural cells death. Thus, it's crucial to understand the molecular basis of the Hippo signaling pathway for determining potential new therapeutic targets against ischemia-associated CNS diseases. Here, we discuss latest advances in the deciphering of the Hippo signaling pathway and highlight the therapeutic potential of targeting the pathway in treating ischemia-associated CNS diseases.